The present invention concerns the field of bottles, flasks and similar volumes made of glass, designed in a general manner so as to contain wine or similar alcoholic products and of which the outer surface has been subjected to a treatment designed to create a decorative or at least original effect, contributing to the identification of the origin of such volumes, or contributing to their customer appeal.
A great variety of such decorated volumes already exists, obtained by very different treatments.
In all the following, reference will be made to bottles, which represent the most usual volumes subjected to such treatments.
A first category of treatments involves removing material, namely glass, from the surface.
An example of a treatment of this type is the spraying of very fine grains of abrasive material, for example corundum, onto the outer surface of the bottle. A hollow graining effect is thus obtained, which is considered to be visually unsatisfactory. Another example is the abrasion of the surface by means of an acid and/or corrosive reagent. Only a satin effect is then obtained by opacifying the wall of the bottle, at the cost of pollution of the environment and working conditions which are dangerous for the operators.
A second category of treatment involves depositing foreign agents on the outer surface of the bottle.
An example of such a treatment by a material applied to the surface of the bottle is the electrostatic deposition of fine particles which must then be "fixed" by means of a suitable coating. Another example is the deposition of particles on the said surface, which has previously been covered by such a coating acting as an adhesive for these particles.
In both cases, the coating does not withstand mechanical friction or heat, which removes the fixing coating, the particles having no tendency in themselves to adhere to the glass.
Yet another treatment by means of the application of foreign particles on the surface of the bottle consists of applying enamels to this surface having the form of coloured particles mixed with a heat-fusible or oily binder, this mixture being applied by using the silk screen printing technique. After application, the whole is fired to the melting point of the enamel, at which the binder evaporates and the particles melt while fusing together and covering the support with a continuous smooth layer. By using successive layers according to the four-colour technique, smooth and continuous coloured decorative patterns are obtained on bottles, which represents a strict limitation of the field of application of this technique.